Oil well torpedo



M D MITCHELL 1,835,666

OIL WELL TbRPEDo Filed Aug. 25, 1923 Tatented Dec. 8, 1235 PATENT OFFHQE OIL WELL roarnno Application filed au ust 25, 1923. Serial No. 659,321.

It is common practice in the operation of oil wells, after the original fiow has declined to a point indicating that freer access of the oil to the well is desirable, to lower a charge of nitroglycerin or other explosive in the well to the level ofthe oil bearing stratum and detonate it, thereby breaking up the immediately surrounding rock more or less and enlarging the diameter of the well at this point.'

For this purpose the charge is accompanied, in common practice, by an electric detonating device, the poles of which are connected by wires to a suitable source of current located above ground at a convenient point.v The wires, however, are a constant source of trouble, often becoming entangled and sometimes broken or short circuited because of the caving in of the wall of the well or from other cause. It is the purpose of my invention to avoid the trouble incident to the use of an electric detonating device by employing a shell or torpedo which is entirely self-contained, requiring no connections to the surface after it has been placed in position, and, therefore, unaffected by caving in of the wall of a well.

. In the accompanying drawings I have shown and in the following specification described a preferred embodiment of my invention; it is to be understood, however, that the specific disclosure is for the purpose of exemplification only and that the scope of the invention is defined in the claims in which it is my intention to cover it as broadly and completely as the priorart will permit.

In the drawings Fig. 1 is an end section partly in elevation of a preferred embodiment of my invention. Fig. 2 a plan of the same; Fig. 3 a transverse section on the line XX of Fig. 1 and Fig. 4 an enlarged longitudinal, fragmentary section showing a detail.

The torpedo shall comprise a main body 5 and a cap or cover 6 which are screwed together at 7 with a water-tight gasket 8 between them. The shell or container should be heavy enough to raise the gravity of the device as a whole above that of the water or oil displaced thereby when the torpedo is lowered into the well so that it may readily sink '18 of fulminate of mercury or other suitable to the desired level. It is also necessary, or highly desirable, that the shell be of sufficient strength to resist the pressure of a high column of water such as is frequently found in oil wells, and water-tight under any condition of pressure to which it may be subjected in a well. The cap is provided with a bail 9 which is rigid therewith for ready attachment to the lowering tackle and the lower pointed end of the main body of the shell provided with a hook 10 to which the main charge of high explosive may be secured.

The interior of the shell contains a charge of nitroglycerin, a -detonating device therefor, and a clock mechanism by which the operation of the detonating device is controlled. The high explosive, which may be nitroglycerin, is shown at 10 in'the'flower end of the shell and the detonating device is mounted immediately above it. The frame 11 of the detonating device rests upon a shoulder 12 formed in the wall of the shell. The frame, which may be a casting, comprises an upper tranverse member or web 13, the lower transverse member M and three connecting longitudinal members 15, 16, 17. The lower transverse member 1 is formed with an internally threaded boss 16 intowhichis screwed a nipple 17, and the latter carries a capsule detonating substance. The nipple is bored at 19, the bore opening into the capsule of explosive when the latter is in position. The upper end of the bore 19 is enlarged at 20 to form a seat for a primer cap 21 which may be of any well known form. The transverse member 14 is bored at 22 to provide a guide for the firing pin 23 which slides longitudinally therein and is adapted to strike and explode the primer cap. A hammer controlled by the clock work drives the firing pm.

For greater certainty of operation, instead of a single such device for exploding the charge, I provide two detonating devices, each comprising a capsule of explosive and means for detonating the same. For this purpose two of the detonating devices are arranged parallel to and adjacent bwCh other and two similar hammers 24, 25 are arranged above for the purpose of driving the respective firing pins. pivoted on a common bolt 26 extending between the connecting members 16, 17 Coiled springs 27, 28 are arranged about said pin and bear against the'respective connecting members 16, 17 and hammers and swing the latter when released to strike the respective firing pins 23. The hammers are so linked to,- gether'as to have only a partial independence of action. For this purpose their free ends are recessed or rabbeted, as at 29, to receive across bar 30 which is loosely connected at its ends to the respective hammers by headed pins 31, '32 extending through holes in the ends of the respective hammers, and of such length as to ermit a limited independent movement of the latter; Thus,when released by the device to be presently described, both hammers are driven toward their respective firing pins, but independently, by means of their respective springs so as to insure the delivery'of a sharp blow on each pin.

The hammers when set and ready for operation are held against the pressure of their respective springs by the engagement of a screw pin 33 with said strip 30. The screw pin 33 is loosely screwed into a threaded opening 34 in the upper transverse member 13 and is formed with a reduced end 35 which is adapted to engage the bar 30 when the hammers are raised and the screw'pin driven in substantially to the limit of its movement.

' The upper end of the screw head is formed or'provided with horns or forked ends 37. A cylindrical alarm clock 38, which may be of any usual or desired design, rests upon the flange 39 of the supporting frame 11, on which it is placed back down. The screw 33 is so located in the transverse member that when the clock is properly placed in the upper end of the shell the horns37 embrace the wings of the finger piece of the stem 40 of the alarm key, so that when the alarm is operated the screw pin is given a number of revolutions, at least sufficient to withdraw the reduced end 35 from the bar 30. When this happens, the hammers are released to gether and each under the impulse of its own spring is driven into engagement with the respective firing pin. To aid in readily positioning the parts in the shell, the inner wall of the latter is preferably provided with a longitudinal groove 43 which is engaged by screw pin 44 in the frame member 11 and a pin 45 with which the clock is provided for this purpose.

The operation of the device will be readily understood. Before lowering it into the well, the cap or cover 6 is unscrewed, the clock and detonating mechanism lifted out, and the hammers set for operation by raising them until the bar 30 passes the pin 35 and then the latter is screwed down to engage said bar. The detonating device is then re-located in These hammers arethe shell in proper position and the clock,

after having been set for the operation of the alarm within a suitable period, is placed upon it in the position above described. The cap is then screwed in place, and a charge of high explosive secured to the hook 10 and the device lowered into the well to be tor edoed. After theperiodfor which the cloc has expired, the charge is exploded by the operation of the device in the manner above described. 7 Because of the weight of the device, there .is no difficulty in lowering it into the well not withstanding any oil or, water contained therein and the contents are thoroughl pros is set tected from the entrance of any liqui By the the anger of failure to explode the charge is reduced to a' minimum. There are no wires to be handled or broken either in lowering the device or afterwards, and it requires no (provision of the two detonating devlces I further attention after being properly lo- I cated.

I claim: 1'. In a device of the classdescribed, a shell, a body of high explosive there'm, a detonating device including a spring-operated hammer,

a screw stop-pin arranged and adapted when in projected position to hold the hammer againstthe action of its spring and when retracted to releasethe same, means for rotating said pin and time-controlled means for normally preventingthe rotation of said pin.

2. In a device of the class described, a, shell, I

a body of high explosive contained therein, a detonating device including a spring-operatedhammer, a screw stop-pin arranged and adapted when in projected position to hold the hammer against the action of its spring and when retracted to release the same, a clock-work mechanism including a rotary shaft, means for rotating the shaft, and means for preventing the rotation thereof during a predetermined interval, and detachable connections between said screw stop-pin and said shaft.

3. In a device of the class described, a shell, a body of high explosive therein, a detonating device comprising a pair of hammers, firing pins operated by the respective hammers, cap seats for receiving caps to be struck by said firing pins, a stop pin for holding both of said hammers in retracted position, and an alarm clock mechanism for withdrawing the stop pin.

4. In a device of the class described, a shell, a body of high explosive therein, a frame, a pair of spring-pressed hammers mounted thereon andhaving limited movement relative to each other, a single stop pin for holding said hammers in retracted position, and an alarm clock mechanism for withdrawing the stop pin after a predetermined interval.

5. In a device of the class described, a shell, 21- body of high explosive therein, a frame in said shell, a pair of hammers in the frame having a limited relative movement, firing pins guided in the frame and operated by the respective hammers, cap seats for receiving 5 caps to be operated by the respective pins, a

cross bar connecting the hammers but permitting a slight relative movement thereof, a

- screw stop adapted when projected to engage the cross bar and when retracted to release the same, and an alarm clock, the alarm shaft of which is loosely connected to said screw stop.

6. In a device of the class described, a shell,

a body of high explosive in the bottom thereof, a fra ework above the body of the explosivef' pair of nipples on the framework, capsules mounted on the respective ni ples and containing a detonating compound cap seats formed in the nipples, firing pins adapted to explode caps on said seats, hammers adapted to strike the firing pins, a rotary screw stop pin on the frame adapted when projected to embrace and hold the hammers and when Withdrawn to release the same, a

pair of ears on said stop pin, an alarm clock, the alarm key of which engages said ears, a cap closing the upper end of said shell, and a bail on the cap.

RK DJM-ITCHELL. 

